I'm curious if moisture from the users breathe builds up over time into a significant quantity inside user inflatable sleeping pads. This may be insignificant, but it seems like quite a bit of moisture would get into the pad when you blow it up and it doesn't really have a chance to excape since it likely condenses on the inside and/or is absorbed my the materials while the pad is inflated.

Do you guys think this is significant? It would be cool to see if these pads weigh more after a dozen nights use than they do originally.

The NeoAir seems the most prone to this (if it does exist) because it has that complex web of fabric going on inside that could retain and trap moisture.